Your tax household size affects the amount of your health insurance premium tax credit.
Your tax household includes all the individuals on your tax return: the tax filer, the tax filer’s spouse (if married filing jointly), and any dependents.
Note: If someone claims you as a tax dependent, you count as part of their household, not your own.
Tax household of one
If no one claims you as a tax dependent, you are not legally married, and you have no tax dependents, your tax household size is one.
Tax household of two or more
If you’re not a household of one, include your spouse (if you’re married and filing jointly) and your tax dependents.
 You can learn more about who you can include as a tax dependent from the IRS.